The Buchwald–Hartwig Amination After 25 Years

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(48), С. 17118 - 17129

Опубликована: Июнь 5, 2019

Abstract The Pd‐catalyzed coupling of aryl (pseudo)halides and amines is one the most powerful approaches for formation C(sp 2 )−N bonds. pioneering reports from Migita subsequently Buchwald Hartwig on aminostannanes bromides rapidly evolved into general practical tin‐free protocols with broad substrate scope, which led to establishment what now known as Buchwald–Hartwig amination. This Minireview summarizes evolution this cross‐coupling reaction over course past 25 years illustrates some recent applications well‐established methodology.

Язык: Английский

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Computational Ligand Descriptors for Catalyst Design

Chemical Reviews, Год журнала: 2019, Номер 119(11), С. 6561 - 6594

Опубликована: Фев. 25, 2019

Ligands, especially phosphines and carbenes, can play a key role in modifying controlling homogeneous organometallic catalysts, they often provide convenient approach to fine-tuning the performance of known catalysts. The measurable outcomes such catalyst modifications (yields, rates, selectivity) be set into context by establishing their relationship steric electronic descriptors ligand properties, models guide discovery, optimization, design In this review we present survey calculated descriptors, with particular focus on catalysis. A range different approaches calculating parameters are out compared, have collected for representative sets, including 30 monodentate phosphorus(III) donor ligands, 23 bidentate P,P-donor view providing useful resource analysis practitioners. addition, several case studies applications covering both maps models, been reviewed, illustrating how descriptor-led catalysis inform experiments highlighting good practice model comparison evaluation.

Язык: Английский

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Mechanistic Analysis of Metallaphotoredox C–N Coupling: Photocatalysis Initiates and Perpetuates Ni(I)/Ni(III) Coupling Activity

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(37), С. 15830 - 15841

Опубликована: Авг. 4, 2020

The combined use of reaction kinetic analysis, ultrafast spectroscopy, and stoichiometric organometallic studies has enabled the elucidation mechanistic underpinnings to a photocatalytic C-N cross-coupling reaction. Steady-state spectroscopic techniques were used track excited-state evolution employed iridium photocatalyst, determine resting states both nickel catalysts, uncover photochemical mechanism for reductive activation cocatalyst. Stoichiometric along with comprehensive study reaction, including rate-driving force unveiled crucial role photocatalysis in initiating sustaining Ni(I)/Ni(III) mechanism. insights gleaned from this further discovery new photocatalyst providing >30-fold rate increase.

Язык: Английский

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Univariate classification of phosphine ligation state and reactivity in cross-coupling catalysis

Science, Год журнала: 2021, Номер 374(6565), С. 301 - 308

Опубликована: Окт. 15, 2021

Which phosphines squeeze together? Phosphine ligands coordinated to palladium and nickel are essential tools for assembling the backbones of pharmaceutical compounds. For decades, descriptors that characterize spatial bulk have helped guide phosphine optimization. However, these tend apply ideal geometries a single ligand. Newman-Stonebraker et al . introduce descriptor considers how ligand conformation might change in crowded environment. Specifically, they found minimum percentage buried volume accurately predicts when one or two particular will coordinate metal center, frequently key determinant successful catalysis. —JSY

Язык: Английский

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Nickel and Palladium Catalysis: Stronger Demand than Ever

ACS Catalysis, Год журнала: 2022, Номер 12(2), С. 1180 - 1200

Опубликована: Янв. 5, 2022

Key similarities and differences of Pd Ni in catalytic systems are discussed. Overall, catalyze a vast number similar C–C C–heteroatom bond-forming reactions. However, the smaller atomic radius lower electronegativity Ni, as well more negative redox potentials low-valent species, often provide higher reactivity oxidative addition or insertion reactions persistence alkyl-Ni intermediates against β-hydrogen elimination, thus enabling activation reluctant electrophiles, including alkyl electrophiles. Another key point relates to stability open-shell electronic configurations Ni(I) Ni(III) compared with Pd(I) Pd(III). Nickel very involve interconvertible Ni(n+) active species variable oxidation states (Ni(0), Ni(I), Ni(II), Ni(III)). In contrast, involving Pd(III) still relatively less developed may require facilitation by special ligands merging photo- electrocatalysis. high Pd(n+) ensure their facile reduction Pd(0) under assistance numerous reagents solvents, providing concentrations molecular Pd1(0) complexes that can reversibly aggregate into Pdn clusters nanoparticles form cocktail Pdn(0) various nuclearities (i.e., values "n"). Ni(0) strong reductants; they sensitive deactivation air other oxidizers and, consequence, operate at catalyst loadings than palladium same The ease robustness versatility for catalysis, whereas variety enables diverse uncommon reactivity, albeit requiring efforts stabilization nickel systems. As discussion, we note easily "cocktail particles" different but (Pd1, Pdn, NPs), behave species" is stable nuclearities. Undoubtedly, there stronger demand ever not only develop improved efficient catalysts also understand mechanisms

Язык: Английский

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Light‐Promoted C–N Coupling of Aryl Halides with Nitroarenes

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(10), С. 5230 - 5234

Опубликована: Ноя. 13, 2020

Abstract A photochemical C–N coupling of aryl halides with nitroarenes is demonstrated for the first time. Catalyzed by a Ni II complex in absence any external photosensitizer, readily available undergo variety halides, providing step‐economic extension to widely used Buchwald–Hartwig reaction. The method tolerates partners steric‐congestion and functional groups sensitive bases nucleophiles. Mechanistic studies suggest that reaction proceeds via addition an radical, generated from I /Ni III cycle, nitrosoarene intermediate.

Язык: Английский

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The Quest for the Ideal Base: Rational Design of a Nickel Precatalyst Enables Mild, Homogeneous C–N Cross-Coupling

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(9), С. 4500 - 4507

Опубликована: Фев. 10, 2020

Palladium-catalyzed amination reactions using soluble organic bases have provided a solution to the many issues associated with heterogeneous reaction conditions. Still, homogeneous C–N cross-coupling approaches cannot yet employ as weak and economical trialkylamines. Furthermore, base-mediated methods not been developed for Ni(0/II) catalysis, despite some advantages of such systems over those employing Pd-based catalysts. We designed new air-stable easily prepared Ni(II) precatalyst bearing an electron-deficient bidentate phosphine ligand that enables aryl triflates amines triethylamine (TEA) base. The method is tolerant sterically congested coupling partners, well base- nucleophile-sensitive functional groups. With aid density theory (DFT) calculations, we determined auxiliary ligands decrease both pKa Ni-bound amine barrier reductive elimination from resultant Ni(II)–amido complex. Moreover, preclusion Lewis acid–base complexation between Ni catalyst base, due steric factors, important avoiding inhibition.

Язык: Английский

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An oscillatory plug flow photoreactor facilitates semi-heterogeneous dual nickel/carbon nitride photocatalytic C–N couplings

Reaction Chemistry & Engineering, Год журнала: 2020, Номер 5(3), С. 597 - 604

Опубликована: Янв. 1, 2020

Dual nickel/photocatalytic C–N couplings are performed with an organic heterogeneous photocatalyst, in oscillatory plug flow reactor. Reaction was complete 20 min residence time, enabling 2.7 g h⁻¹ throughput and 10-fold catalyst recycling.

Язык: Английский

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Methyl Esters as Cross-Coupling Electrophiles: Direct Synthesis of Amide Bonds

ACS Catalysis, Год журнала: 2019, Номер 9(5), С. 4426 - 4433

Опубликована: Апрель 18, 2019

Amide bond formation and transition metal-catalyzed cross-coupling are two of the most frequently used chemical reactions in organic synthesis. Recently, an overlap between these reaction families was identified when Pd Ni catalysts were demonstrated to cleave strong C–O present esters via oxidative addition. When simple methyl ethyl used, this transformation provides a powerful alternative classical amide formations, which commonly feature stoichiometric activating agents. Thus far, few redox-active have been activate C(acyl)–O alkyl esters, makes it difficult perform informed screening challenging needs optimization. We demonstrate that bearing diverse NHC, phosphine, nitrogen-containing ligands can all be enable their use direct formation.

Язык: Английский

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Nickel-catalyzed electrochemical reductive decarboxylative coupling of N-hydroxyphthalimide esters with quinoxalinones

Chemical Communications, Год журнала: 2019, Номер 55(97), С. 14685 - 14688

Опубликована: Янв. 1, 2019

The first example of electrochemically enabled, NiCl₂-catalyzed reductive decarboxylative coupling N-hydroxyphthalimide esters with quinoxalinones was developed.

Язык: Английский

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